


Mistakes

by sydwtr



Category: Critical Role (Web Series)
Genre: Accidental Voyeurism, Alternate Universe - Modern Setting, Background Relationship: Vax/Keyleth, Background Relationship: Vex/Percy, Drunk Sex, F/M, Masturbation, Sex Outdoors, Sibling Incest
Language: English
Status: Completed
Published: 2018-12-09
Updated: 2018-12-09
Packaged: 2019-09-13 15:00:56
Rating: Explicit
Warnings: Underage
Chapters: 1
Words: 4,950
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/16894785
Author URL: https://archiveofourown.org/users/sydwtr/pseuds/sydwtr
Summary: It's the sort of mistake that he should just forget about, but now Vax can't get his twin out of his head.





	Mistakes

It was an accident, he tells himself, lying in bed and staring at the ceiling, trying not to let the scene replay over and over behind his eyelids. It was an accident and he was just… too startled to look away. That’s it.

The late night noises coming from Vex’s room hadn’t exactly woken him up, he’d been scrolling on his phone instead of sleeping like usual, but they’d caught his attention. And he almost recognized them, the little sounds of his sister trying to hide her tears in her pillow. He’d slid out of bed and gone into their shared bathroom, intent on asking if she was okay, if she needed anything.

Vax had meant to be a good brother, really.

He justifies that to himself over and over as he tries to ignore the erection throbbing in his shorts.

Her light was on, a dim glow that left him in shadows, standing in the cracked open bathroom door. His lips had parted to call her name and then he’d _seen_ her and all sound had dried up in his throat.

Vex’ahlia, his twin, the other half of his soul, the sister he grew up so close to that they had no secrets…

For half a second, he’d still thought she was upset. Her hand was over her mouth, muffling the noises now, but his eyes tracked down and he _saw_ her. Fingers between her spread legs, pumping in and out of her pussy with effort. Her tank top was hiked up over her breasts, leaving them free to move with her labored breathing, her nipples hard despite the room’s warmth. _Because she was playing with them,_ the traitor inside his brain whispers as he fights not to relive the moment, the same traitor that told him to grip himself through his basketball shorts and keep watching. He repeats the motion without thought now, squeezes absently, rhythmically and thinks about his sister’s back arching off the bed, her mouth open, her thighs shaking as she let out a moan.

“ _Percy_ ,” she’d whispered and that had startled him out of it, distaste curling in his throat followed by horror as he realized what he was doing, what he was _watching_.

Vax yanks his hand away from himself as if burned, turns on his side and tucks both hands under his pillow as he curls up. It’s not his business. He shouldn’t have looked in the first place and he should have looked away as soon as he realized.

He wonders what his sister’s nipples would taste like in his mouth.

He wonders what Vex’s pussy would feel like around his cock.

Oh, god, he’s going to a special hell.

* * *

“Vax,” Vex leans into his room wrapped in only a towel, still wet, her hair hanging in damp waves over one shoulder and he _jolts_ with the glimpse of thigh that he’s seen a million times but suddenly makes him think of too many other things. “Have you seen my hair straightener?”

 _I’ve seen you masturbating_ , he thinks but doesn’t say, nodding slowly, still processing. He stands up, crosses from his desk to the door and brushing her, aware, _too_ aware, of how close her warm, naked body is to him. He crouches down and pulls the straightener from a pile of things in his cupboard under the sink, passes it over to her with something like a smile.

“Your hair looks better wavey, you know.”

“Does it?” Vex holds the straightener as he stands, frowns at herself in the mirror. “I was going to straighten it for…”

He watches her face in reflection, reaches out slowly and cards his fingers through her damp hair. “I think you’ll look great no matter what…” His body is so close to hers, her back pressing against his chest as she relaxes into the fingers that start at her scalp and work down. Her skin burns under his fingertips as he gently combs out her hair, lightly twists it into a loose braid that hangs over her shoulder. “Are you going out?”

There aren’t secrets between them except for the horrible new one Vax keeps, so Vex nods and smiles eagerly. “I got invited to a party. Percy’s bringing me.”

He doesn’t warn her that it could be a trap, because she knows… and she’s a good judge of character. He doesn’t tell her that he’ll come get her if she’s wrong about him, because she knows. Instead Vax rests his chin on her shoulder, wraps his arms around her barely-covered body and squeezes her close to him. “I love you, Vex’ahlia.”

Her hand pats his gently. “I love you, too, Vax. Now, let me go, you weirdo. I still have to get dressed and do my make up and he’s going to be here in an hour.”

Vax lets her go, heads back to his room and shuts the bathroom door behind him. He doesn’t think about her body pressed up tight to his and he _definitely_ doesn’t get hard.

* * *

The twins have the house to themselves for a weekend--some business related trip that their father goes on, that he takes their step-mother and half-sister along with and doesn’t even bother to offer to them--and Vax decides to really shake it out of his system.

He’s had a casual thing with Keyleth for a while now, something on the cusp of becoming a true romance if the two of them would just get over themselves (Vex’s words, the last time he’d lamented his romantic affairs to her). So he invites her over and he sneaks a bottle of wine up from the cellar and the two of them put on a movie they’ve both seen before and get under a blanket together on the couch. They pass the bottle back and forth and kiss with wine on their lips and Vax swears that he’s only thinking of her when her head disappears beneath the blanket and his pants are opened up, but looking down he sees a peek of brown hair instead of red and his cock jumps in her hand, his hand cramming over his mouth to muffle it when he moans his sister’s name.

If Keyleth catches the mistake she doesn’t say anything, bless her, just crawls onto his lap and kisses him drunk as she lets his cock slide into her.

He definitely isn’t thinking about Vex’s naked body on her bed when he cums into the condom. Definitely not. His mind is focused on Keyleth, on the taste of her skin under his lips and the feeling of her pussy around his cock and thoughts of his sister, just upstairs in her room probably not listening to him get laid in the living room, are the last thing on his mind.

He and Keyleth stumble up to his bedroom after that, shuck clothing and he lets her sleep in one of his t-shirts, heads to the bathroom to brush the taste of wine out of his mouth before crawling into bed.

Vex is there, in only a t-shirt and panties herself, a toothbrush in her mouth. “Have fun?” She asks around the foaming toothpaste, leaning over the sink and spitting. The t-shirt rides up. He tries and fails not to stare at her ass until she stands up straight again and meets his gaze. “Don’t be a sicko, Vax. You’ve got Keyleth for that sort of staring.”

 _Want_ buzzes into him and he takes a step towards Vex, almost stumbles and leans on the sink. What is he _doing_? She’s his _sister_. “‘M drunk,” he slurs out, aware of just how true that sentence is as the world tilts first to the left and then to the right. “Oh, fuck.”

He makes it to the toilet, at least, paints the bowl with expensive red wine and feels a hand rub his back in comfort, hears his sister’s soft words encouraging him to puke up the impending hangover.

Vex gets him a glass of water and makes him drink it slowly, allows him to lay his head in her lap there on the bathroom floor with something like tolerance. Vax stares up at his sister, beautiful, even in this light, and his mouth moves faster than his brain.

“I saw you… the other night… you were… you were…”

“Vax, no.”

“Did you wan’ me to see?”

Her finger presses over his lips and he kisses it, draws it into his mouth and swirls his tongue around it. “It’s wrong.”

“You’re pretty.”

That makes her laugh and he beams, feels her smile embolden him. The world shifts again as Vax sits up, as he holds his sister’s smiling face with one hand and presses his lips to hers in a way that’s too sloppy drunk to even be called a kiss.

Her eyes are wide in surprise, her mouth pliant under his tongue. Vax tastes her, the minty sharpness of her toothpaste and the sweet softness of _her_ and then her hands are on his bare chest, pushing him away. “Vax. No.”

He lets his hands drop, down her neck, down her shoulders and over her chest, over the swell of her breasts and the stiff peaks of her nipples. Into her lap, onto her thighs where his thumb rubs a slow line over her pussy through her panties. “Vex…”

“Vax…” Her hand holds his wrist but she doesn’t move him away, doesn’t tell him _no_ or _stop_ or anything at all. Her teeth sink into her lip, eyes on his face.

“Did you want me to see?” He asks again, strokes his thumb over her again and feels the whole-body shiver that it pulls from her.

“Of course not.”

“Did you know… I was watchin’?” He presses down a little, hears her take in a shaky breath that’s almost a moan as he rubs her clit through her panties.

“I knew.” The tears in her eyes make him stop, the sob in her voice. Vex rocks her hips into his hand, her nails digging into his wrist. “I knew, Vax… and I liked it…”

“Vex…” He leans into her, kisses her again and this time she returns it, this time her tongue plays with his and her body moves closer. She climbs into his lap, presses her thighs to either side of his hips as her arms wind around him. He can feel her and he’s sure she can feel him, growing hard in his shorts once more.

“It’s wrong,” she whispers, forehead pressed to his, arms wrapped over his shoulders as her hips grind down on him. “We’re making a mistake, Vax.”

Drunk logic says nothing that feels good is wrong, or a mistake. Slightly more sober logic says that the only mistake they’re making is doing this on the bathroom floor. Actual logic tries to butt in that they’re _siblings_ and _twins_ and _Keyleth is in the next room_ and he listens to one piece of advice from that.

“I love you, Vex’ahlia.” He kisses her again, wonders just when his hand snaked up her shirt and his thumb started rolling her nipple. She moans into his mouth, arches her back away from him for a second before diving in again, hungry.

“You’re not going to be my first,” she whispers into his ear, her cheeks flushed. “The other night, at the party, Percy and I…”

“I don’t mind. Was he good to you?”

“He was… polite.”

Vax wants to fuck her until she forgets him, until she forgets herself, until the only thing she can think of is her brother. He doesn’t tell her this, but he rocks his hips up into hers and speaks low in her ear. “You know you’re not my first, either. Experience isn’t a bad thing.”

They can’t tonight. Not on the bathroom floor, not without a condom, not without soberly considering the consequences. With effort, they pull away from each other, touches lingering until Vex goes to her room and Vax goes to his. He presses into Keyleth’s sleeping form and holds her tight, thinks about falling asleep with his sister in his arms.

* * *

Driving Keyleth home is fine, the usual sort of afterwards they have where they listen to music and laugh and don’t kiss in her driveway because they can both see the twitch of curtains as her dad watches. It’s fine. He kissed her goodbye at his house, over coffee and sleepy smiles.

She’s who he should feel a pulse of need for, watching her head into the house before backing out of the driveway. She’s who he should be thinking about, not Vex, not his damn _sister_.

He can still taste Vex’s lips on his if he thinks about it.

Drunk or not, Vax remembers enough of the previous night. He remembers the kissing, the touching, the soft words there in their bathroom. He remembers her being hungry for it, wanting it just as bad as he had.

She knew he watched. She liked it. He remembers that clearly.

Vex is on the couch when he gets home, under the blanket that he hasn’t bothered to put away yet, her eyes on the phone and Netflix on in the background. Vax joins her, wraps his arms around her and holds her to himself as she gets comfortable against him. His fingers stroke through her hair, lips pressing to her temple. Early afternoon, no one else in the house, just the muted sounds of the television and their soft breathing.

It can’t be _wrong_ , Vax tells himself, when it feels right.

“Do you want lunch?” He asks against the top of her head, shifting his arms, tilting his head as she turns to look up at him.

“Mm… I just had breakfast, though… like…” She looks at the time on her phone, her nose wrinkling. “Okay, like four hours ago. Maybe lunch is a good idea.”

They head to the kitchen together, rummage through the fridge and pantry and come up with soup and sandwiches. Vex stands over the stove, stirring the pot as the soup warms and Vax steps up behind her, wraps his arms around her waist and presses his chin into her shoulder. “ _Was_ he good to you?”

He can feel the stiffness, the dawning realization in her that he remembers that part of last night, and if he remembers that… “Vax, don’t…” Vex squirms in his arms and he tightens his grip for a moment, holds her steady until she goes still. “Don’t be jealous, brother.”

“I’m not jealous. I just know how _people_ are.” He eases up, moves back and pours two glasses of iced tea to go with lunch. “I’ve been there, too, Vex.”

“He was fine. Polite. Caring. He… he _wanted_ me there and he wanted me to have a good time and I _did_. It wasn’t… like that.” She dishes up soup, sits down with him at the table and frowns. “I didn’t call you crying, after all, did I?”

“That’s fair.” Vax’s hand brushes her hair back once more, before they both settle in to eating lunch. The rest of it can wait. The rest of it he can approach slowly. They’re left unsupervised for at least another three days, a long weekend of just the two of them in the big quiet house.

* * *

The thing about it is, they’ve done it before. They took baths together when they were children, have seen each other’s nude bodies before. They asked questions of their mother, when they were very young, and she explained things frankly and clearly.

So when Vex asks him with a glint in her eye if he wants to go swimming once the sun has gone down, he doesn’t go for his trunks and isn’t surprised that she doesn’t go for her bikini. The high fence and higher shrubs in the backyard keeps prying eyes away, not that there are any around their father’s house. Vax brings out two towels and flips on the walkway lights that surround the pool, illuminates the path as his sister turns on the stereo system and the jets for the hot tub. They strip outside, toss their clothes onto lawn chairs without care, without shame as they jump into the water.

This is, after all, something they’ve done before. The sexual thrill of it may be new, but the naked swimming has been their little rebellion for most of their teenaged years.

They splash and dunk each other under in the neck deep water of the pool, laughing and teasing, wet bodies sliding against each other. Vax manages to lift Vex out of the water and throw her into the deeper end of the pool, almost doubles over laughing as she scrambles back to him and abruptly returns the favor.

“It’s because you’re so scrawny,” she teases when he swims up to join her at the side, pouting. Her fingers slide down his chest, curve around his hip and squeeze. “All skin and bones.”

“You’re not exactly made of muscle, either.” He pokes her stomach pointedly, the smooth flat plane of skin below the water.

“Well.” Vex braces her hands on the barrier between the pool and the hot tub, boosts herself up and slides across the smooth tiles to land in the warmer water there. Her brother’s eyes track over every exposed inch of her as she does so, unashamed. “I’m still stronger than you.”

“Are not.” He climbs over the side, slips into the hot tub with her and finds a comfortable position with the jets at his back.

“Oh?” Her body presses closer to his, naked form settling into his lap with her back against his chest. “I definitely threw you farther, brother.”

“That doesn’t mean you’re stronger.” He wraps his arms around her waist, sets his chin on her shoulder and doesn’t try to suppress the warmth that rises in his belly as her bare skin settles on his. They’re going to do this. Right here in the hot tub, they’re going to--

Vex sighs, leans back into him and sinks down, lets the water cover her up to her neck. “It’s really, really fucked up and wrong, you know.”

“I know.”

“And if Dad ever found out, he’d probably… he’d make us go away from each other.”

“Then we don’t let him find out.”

She spreads her legs to either side of his, trails her hands down her body slowly, then back up to cup her breasts. “Vax…” Thumbs brush her nipples, fingers pinching lightly and tugging. “Mm… watch me, first… Don’t touch me… Not yet…”

He watches, eyes intent, his breathing growing shallow. Below her his cock is stirring, he’s sure she can feel the hardness pressing into the curve of her ass as his sister sits on his lap and touches herself, plays with her nipples until they’re standing up stiff in the warm water. Vex arches her back up slightly, lets them poke out of the water in the cool night air and groans. “Play with my tits, brother. But keep watching.”

“Fuck,” he breathes heavy into her ear, his eyes on her hands as they begin down her body. He cups her breasts, squeezes the soft flesh and begins toying with her nipples just as she had been.

Under the water it’s more difficult to see what she’s doing to her pussy, but Vax can feel it and hear it as Vex pleasures herself. Her body twitches and trembles against his, small whimpering moans from her lips as she gets herself off. Her head drops back over his shoulder, her breathing loud in his ear as her movements speed up, breathless words for only him to hear.

“I’m gonna cum, Vax, I’m gonna--mm… Tell me I can, brother, tell me to cum for you…”

“Not yet,” he hisses back, a sudden urge of _want_ rushing through him. He moves his hands from Vex’s tits to her waist, lifts her off him and turns her to face him. He shifts their position, sets her on the lip between the hot tub and the pool, kneels on the bench and kisses a quick line down her torso, tastes her skin. “I wanna taste you, Vex.”

“Oh, hell…” Her legs wrap over his shoulders, the fingers rubbing her clit going still, being batted away by his. “Do it. Taste my cunt.” She braces her hands on the edge of the divider, tilts her head down and watches with her lip caught between her teeth.

Vax grins, decides to taunt her just a bit. He kisses up one thigh to her pussy, barely brushes his lips against her before moving down the other thigh. His hands grip her hips, keep her cemented in place as he licks his lips and looks up at her. They’ve been good at silent conversation for most of their lives, it’s no struggle to understand each other now. A last chance to say no before they do something completely irreversible. An opportunity neither is taking.

“Fucking _do it_ already, Vax.”

He tastes her, tongue delving inside, swirling around her clit and flicking the sensitive nerves. On either side of his head he can feel her thighs shaking, already so close to the edge and taunted right up to it by just a lick. He buries his head between her legs, works her over in all the ways he knows how, all the ways he’s been dreaming of since that night.

Vex cums with her hands clapped over her mouth and still he hears her moan his name. He rides her through it, lets her grind herself into his face until she’s shaking and gasping for breath and only then does he come up for air, only then does he trail his lips back up her torso, over her chest and let her taste herself on his tongue.

“Vex…” His arms wrap around her, his cock hard against her belly, pressed between them. “Holy fuck.”

“Mmm… yeah…” Her head drops to his shoulder, her hands sliding easily up and down his back. “I want you to fuck me.”

Vax swallows audibly, grinds into her with a little whine. “Right here?”

He can feel her grin against his neck, her words low in his ear, sending fresh hot thrill racing up his spine. He pulls back enough to see her face, to make sure she’s serious.

“Okay.”

* * *

Of all the wrongs they’re committing this weekend, this might be the worst of them. Vex falls backwards onto their father’s bed and yanks Vax down with her, kisses him hot and hard with her fingers laced into his hair.

“Oh fuck, Vex, fuck, come on…” His hips jerk into hers and she laughs, lets him move his head down to press his forehead to her shoulder, lets him pretend to have some sort of self-control for a little while.

“You’re gonna fuck your sister in your bastard of a father’s bed, Vax. Is it really that exciting?”

“ _You’re_ that exciting.”

The heat of want in his voice makes her teasing dry up, her body pressing tight to his. So maybe he’s not the only one struggling for self-control.

“Come on, I wanna feel your cock,” she whispers, rocking her hips up to meet his, her legs wrapping around him. “I wanna feel you go all the way inside me, Vax.”

It’s a _sin_ how hot his sister is. It’s a sin how much her words make him want her, and she fucking knows it. Vax sits up enough to position himself, his eyes raking up and down her body once more before he slides in.

It’s absolutely wrong how well he fits home in her.

They hold each other, bodies pressed together, forgoing movement in favor of proximity. Bypassing the notion of fucking for just the pleasure of feeling. Their lips meet again and again, breathless kisses that leave them both dizzy.

When Vax starts fucking her in earnest, starts moving his hips in shallow thrusts and shoves a hand between them to rub her clit, she lets herself go with it.

In every way, it’s better. Better than what she’s had before. They really are like a mirror for each other, inside and out, and Vax fits in her so perfectly, fills her up so completely, that she can’t help but match him. Her body draws him in and holds him there, now complete, the two of them now one, and Vex doesn’t even pretend to care that it’s wrong.

She cums twice before he goes still again, breathing hard and whispering her name, filling her up with his seed. Vex reaches down when he pulls back, fills herself with her fingers when he slips out of her and cums a third time from her own hand, brings it to her lips and tastes their mingled flavors. Her clean hand threads into Vax’s hair, pushes his head down until he’s level with her cunt. “Clean me up.”

Her body shakes and twitches as he licks the cum from inside her, tenses with impending orgasm that never quite reaches its peak. Limitations exist, even in this new world of sexual exploration that they’ve found.

Vax kisses her again with cum on his lips and she holds him tight to her, molds her body to his as exhaustion starts to settle in.

“Mm… Love you, Vax’ildan.”

He buries his face into her shoulder, his arms wrapping around her tightly. “Love you, Vex’ahlia.”

They’re going to hell together.

* * *

When they were six they took baths together and Vex pointed one night, as their mother dried Vax off and wrapped him in a towel, to between her brother’s legs. “What’s that?”

“That’s your brother’s penis. Or peepee. It’s his private area.” She patted his butt lightly, held out a towel for Vex.

“How come I don’t have one?”

“Because different people are born with different things. Usually it’s a matter of if you’re a boy or a girl.” She wrapped the towel around Vex, rubbed vigorously up and down her arms.

“So what do I have?”

“You have a vagina, or…” She hummed, thoughtful. “A veevee. That’s your private area.”

* * *

When they were thirteen their father took them away and the first thing he did was make them start sleeping in separate beds. Separate rooms. It wasn’t right, he said, for children their age to share a bed. Especially not a boy and a girl.

They snuck into the same bed regardless for almost a month before they really settled into the new house, the new lives. Innocent to the core, holding each other only for the familiar comforts of a childhood they’d been ripped away from.

* * *

When they’re sixteen they wake up naked together in bed, arms around each other and the sin they’ve committed heavy on their shoulders. Vax kisses Vax’s neck and jaw gently until she stirs, turns her mouth to him and greets her with a chaste brush of lips.

She’s sore in such a good way, boneless and sated somewhere deep inside herself. His arms around her are strong, secure, safe, the same comfort that they were in childhood. There’s something else, however, a new feeling that flutters across her stomach when his hand snakes down and cups between her legs. Vex moans low into the pillow as he rubs her clit, grinds herself back into him.

“Vax…”

“Morning, sister.”

It’s the title, the reminder, that makes her jolt with pleasure. The little whisper of just how forbidden what they’re doing is.

He brings her right to the edge with his hand and then stills, leaves her panting, whining, clawing at the sheets. His index finger taps her clit and her whole body shakes with the urge to cum. Vax’s mouth is at her ear, his words low and fast. “You’re so fucking hot, Vex, fuck… I wanna fuck you in front of a mirror, just so I can show you how good you look when you’re about to cum… So that you can see for yourself just how irresistible you are.”

The warmth in her isn’t just arousal from his hand, it’s the love his words are laced with and she reaches down, grasps his hand and laces their fingers together. “Do it. And then I’ll jerk you off and show you just how fucking good you look when you’re fucking your sister.”

He moans in her ear, his cock twitching against the back of her thigh and Vex releases his hand to reach back, to grasp him and line him up. Her leg wraps over his, her back pressing to his chest as he thrusts forward and enters her, jolts her right back to the precipice she’d been coming down from.

Their bodies move in slow tandem in bed, late morning sun across the rumpled sheets as they fuck. Vax rubs her clit and she moans his name without shame, feels him twitch inside her. It’s slower this morning, easier, orgasm that takes her not like jumping into a pool but like being engulfed by slow rolling waves. Vex stays on the high of orgasm until Vax fills her again, until he falls back breathing hard and whispering her name.

They’re sixteen and after they finally drag themselves from their father’s bed, Vex lets her brother fuck her throat in the shower while they try and fail to keep their hands off each other long enough to clean up. She dresses in a short skirt and a low cut top and purposely doesn’t wear any underwear so that she can sit on his face and ride his tongue to orgasm whenever she wants during their day home alone.


End file.
